In a power adjustable heat pump heating apparatus, when a set temperature in regard to room temperature is set by, e.g., a remote controller or the rotational speed of a compressor, i.e., heating power is controlled in dependency upon a deviation between a room temperature and a set temperature. In this case, at the time of a large temperature deviation, i.e., a so called heavy heating load, the compressor is driven at a higher rotational speed. In contrast, at the time of a small temperature deviation, i.e., a light heating load, the compressor is driven at a lesser rotational speed.
In the case where the operation of a heating apparatus is initiated under the circumstance where a room temperature is considerably less than a set temperature, the room temperature gradually rises towards the set temperature. As a difference therebetween gradually becomes smaller, the rotational speed of the compressor also lowers. As the rotational speed of the compressor decreases, the temperature of air blown off from the heating apparatus into the room lowers. For this reason, when the room temperature becomes close to the set temperature, persons in the room might feel an uncomfortable chill.